As far back as twenty years ago, suggestion was made that clothes could be sterilized by irradiation with microwaves. Such suggestion can be found in U.S. Pat. No. 3,605,272; issued: Sept. 20, 1971.
However, despite this disclosure, very little is definitely known about killing bacteria using microwave energy.
A careful survey of scientific articles and journals indicated that parameters and mechanisms by which bacteria can be killed by microwaves is not well understood. In fact, there are published articles that even suggest that bacteria growth can be enhanced by microwave irradiation.
On this note, the present inventive research, set the task of developing a verifiable method for sanitizing clothes and fabrics heated and dried by microwaves.
Using an apparatus similar to that described and shown in U.S. patent application, Ser. No. 092,621, clothes and fabrics were heated and dried by multiple magnetron units, each producing approximately 700 Watts, and operating at approximately 2,450 MHz. The multiple microwave sources were cross-polarized. The tested fabric articles respectively contained different strains of bacteria, such as: E. Coli; Salmonella; Shigella, etc.
It was discovered that bacteria could be killed using microwaves, and that the effective mechanism by which this was accomplished was not entirely heat dependent. In other words, the microwave field effect itself was a contributing mechanism by which decontamination was accomplished.
Thus, heating and drying by microwaves provides a sanitizing advantage that ordinary heating and drying techniques cannot accomplish.
Furthermore, it was also discovered that the airflow necessary for carrying away evaporated moisture, could seriously complicate the sanitizing process by introducing air-borne contaminants.
It was further discovered during the testing, that the fabrics could be heated by microwaves without removing the moisture from the drying chamber. Heated in this way, it was observed that an enhanced sanitizing effect was obtained. Bacteria were more easily killed by the combination of the microwave field effect and the accumulated and heated moist air which was now trapped within the heating chamber.
However, the microwave field effect in combination with the confined, heated water vapor (steam) proves a synergy in sanitizing fabric heretofore unknown.
Sanitizing fabric by microwave energy is now conclusively a reality.